With the invention of compact audio discs, the protection and storage of these discs presented a problem for manufacturers as well as consumers. At first a single compact audio disc was packaged in a rectilinear clear plastic box. One prior art construction to store these single discs was a tray with upper and lower opposed spaced parallel elongated ribs, with the spacing between the ribs being sized to slidably receive one single disc box.
Long-playing works as well as multiple related works had to be recorded on two discs which gave rise to the dual disc plastic box. This plastic box folded open in a book-like manner in two opposed sections, with one disc being housed in each section.
The art then desired a storage tray which would readily accept both the single disc boxes as well as the dual disc boxes, so that a consumer in purchasing a disc storage tray would be assured that the tray would accomodate both single and dual boxes in a reasonable storage mode.